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Comment by fr0sty | Hacker News Reader

What is the disk footprint of the existing SVN repository? "100s of GBs"? git's worst case repository size is equal to or slighly larger (few % probably) compared to an SVN repository.

Git will deduplicate all of your binaries across branches (and if you are clever, across repositories, but that's another story) so worst case you will only have one copy of any binary file no matter how many times it appears in your history.

That is not to say that git may be a poor fit for your current project+organization for other reasons but a blanket assumption of ("repository would be too huge") is not generally accurate.

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He didn't say the repo would be too huge for the server where the svn repo lives today. He said it would be too huge for the laptops.

The binaries are already deduped, that's why they live in svn.

The OP made no mention of how large the SVN repo is, but rather speculated that the git equivalent would be "100s of GBs".

Had the statement been: "Our SVN repo is alreay 100s of GBs in size" then yes you are not likely to want to stuff that onto a laptop but that was not the claim. The claim (without rationale) was that the git equivalent would be 100s of GBs which is similar but not at all the same.

one assumse 1:1ish correspondence the other applies an unstated multiplier SVN * n = git where n > 1 (and significantly so.)

In reality the multiplier appears to be negative in many cases:

> Git's repositories are much smaller than Subversions(sic) (for the Mozilla project, 30x smaller) [1]

[1] https://git.wiki.kernel.org/index.php/GitSvnComparison

He speculated that the entire history (which I would say is equivalent to the SVN repo) is 100s of GBs. We are assuming a 1:1 svn repo to git repo ratio.

Mozilla's ratio would be relevant if they were storing something like the visual studio installer in their repo. They aren't, so it's not.

The binaries (including debug symbols etc.) are the bulk of that size, and storing all revisions locally will almost certainly add up to non-trivial size for a laptop. Unless git has some kind of magic differencing algorithm specifically executable code and debug symbols, I don't really see a way it could work - that's my rationale.

Of course, such algorithms do exist - Google's Courgette - but I don't think git is using them (I have looked) and doubt they are tuned to e.g. Borland TDS/RSM/etc. symbols.

I have no idea how large the svn repository is - it's stored on a SAN and run on a dedicated server I only interact with via svn. It could be many terabytes for all I know; and of course, my team's project tree isn't the only thing in the full repository.

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